Process for obtaining tricalcium saccharate rich in sugar and poor in lime and of alpha very high degree of purity



March 15, 1932. c, STEFFEN, JR 1,850,036

PROCESS FOR OBTAINING TRICALCIUM SACCHARATE RICH IN SUGAR AND POOR INLIME AND OF A VERY HIGH DEGREE OF PURITY Filed April 27, 1926 PatentedMar. 15, 1932 PATENT OFFICE CARL STEFIB'EN, 33., OF VIENNA, AUSTRIAPROCESS FOR OBTAINING TBICALCIUM SACCHABATE RICH IN SUGAR AND POOR INLIME AND 01 A VERY HIGH DEGREE OF PUBI'IY Application filed April 27,1928, Serial No. 105,011, and in Austria May 18, 1825.

This invention relates to a process for obtaining tricalcium saccharaterich in sugar and poor in lime and of a very high degree of purity.

"5 It is known that molasses sugar is obtained by various extractionprocesses wherein the sugar is precipitated with calcium made as aninsoluble tricalcium saccharate. The tr1- calcium saccharate suspendedin the liquid is brought to a higher concentration by filtration throughfilter presses, so that the saccharate filtered ofl' still has a watercontent of about 70%, and in this water is still to be found the samepercenta e of non-sugar elements as was present in t e precipitatlonliquid. The process therefore does not succeed in completely separatingthe sugar from the non-sugar elements, but there always remains a partof the non-sugar elements in the water content of the saccharate. Inorder now partly to remove from the saccharate the quantities ofremaining non-sugar elements, or in order to obtain from the outset aslow a content as possible of non-sugar products in the water remainingin the saccharate cake, various methods have been proposed, of whichhowever none has led to practical success.

It has been found thatlif. from 1 to 3 times the quantity of the sugarcontent of a cold low-percentage (0.8-2%) sugar solution (dilute juices,sweet washings, waste liquids or molasses), is introduced in the form ofseparated tricalcium saccharate and mashed into said solution, saidtricalcium saccharate decomposes only in part and the lime liberated bythe decomposition combines immediately with the sugar of said sugarsolution to form a soluble sugar lime compound, Whilst the remainder ofthe tricalcium saccharate remains completely undecomposed. If finelypowdered lime is now added to this mixture, the soluble sugar limecompound present in the mixture is precipitated by the lime as aninsoluble sugar lime compound. 4 The saccharate thus obtained isseparated by pressing in filter presses for the purpose of increasingthe concentration. This saccharate has the same composition as regardsthe relative proportions of sugar and lime, as that obtained by treatingan ordinary sugar solution with lime and is found to be a tricalciumsaccharate rich in sugar and poor in lime and of very high purity, thecoeificient of purity being 97 to 98.

A second way of carrying out the invention 55 consists herein, that atricalcium saccharate, which is obtained from molasses, is mashed withlime water and the masked saccharate is added to a low percentage coldsu r solution. The lime set free by the partia decom- 50 position of thetricalcium saccharate, which has resulted from the mashing with limewater, combines with the sugar of the low percentage sugar solution toform a soluble sugar lime compound. Fresh quantities of powo dered limeare added to this saccharate mashed in the sugar solution for furtherprecipitation. The result is identical with that o the first method.

A further method of carrying out the roc- 7o ess consists in acombinat1on of one o the processes hereinbefore described with a knowncombined precipitation and urifying process for the treatment of sugarfime.

According to the said known process an impure sugar solution of a highconcentration (from 5 to 7% sugar) is precipitated to form tricalciumsaccharate and the liquid containing the latter is passed into a filterpress until the pressure rises from 1 to 2 atmospheres, 30 whereupon thecake obtained is washed with a liquid containing tricalcium saccharatewhich liquid is produced by precipitating with lime a low percentagesugar solution (2%) from molasses, or a low grade syrup, which conse- 5quently has a much lower non-sugar content.

By this means the high non-sugar content of the tricalcium saccharatecake, first obtained, is displaced and a tricalcium saccharate of ahigher degree of purity is obtained. 00

In both of the above described methods according to the presentinvention, there is addedto an approximately 0.8 per cent sugar solution(preferably dilute juices), about sugar, and mashed in the form oftricalcium sacchara-te such as mashed sugar lime, and subsequently freshquantities of powdered lime are added for precipitating the sugar stillpresent. This precipitation li uid so formed has a non-sugar content 0about 100 0.31% and, in accordance with the present invention, is usedas the washing liquid in the filter press in carrying out the said knowncombined precipitation and purifying process. The quantity of the saidwashing liquid of high purity is three to three and a halt times thequantity of the contents of the press and is pressed in the filter presstill apressure of 4-5 atm. is reached. Then the liquid from the firstprecipitation, which is of high nonsugar content is substituted by theliquid of the second precipitation which is poor in nonsugar content. Inthis manner saccharates of purity co-efficients 97 to 98 are obtained.In this operation an amount of about 25% of the washed saccharatesobtainedis returned into the precipitation operation, for washingpurposes, whilst the other 75% are led away into the separating stationof the factory.

The economic result of the invention lies in the production ofsaccharate of very high degree of purity, and in which the consumptionof lime is the same as with the normal precipitation. The achievement ofhigh purities is of great importance for the factory operation, sincethe purity is not impaired, but is increased, by the introduction of thesaccharate into the dilute juice. Particularly in the manufacture ofwhite sugar is it of great importance to manufacture saccharates of highpurity, because, in order to produce sugar of quality, juices of lightcolour are necessary. The saccharate of low purity contains howeverlarge quantities of colouring matter, whereby the juices in the factorybecome. very dark, from which products of good quality can be reparedonly with difliculty. A further a vantage consists herein, that thisprocess permits a higher concentration of the added liquid of the firstprecipitation, whereby firstly the sugar losses are decreased inconsequence of the quantities of waste lye being diminished and secondlywaste lyes of higher concentration are obtained, which makes a lyeevaporation more profitable.

The drawing shows diagrammatically by way of example one form ofconstruction of an apparatus for carrying out the process.

From the container L solution flows through the pipe a, and from themolasses container W molasses pass through the pipe 6, into theprecipitating apparatus F so that the added liquid has a sugar contentof about 6 to 6.5%. This added liquid is subjected to a normalprecipitation process, for which purpose the pump T sucks the liquid tobe precipitated through the pipe 0 and forces it through the cooler Kinto the container S in which finely divided powdered lime iscontinuously strewn through the lime supplying apparatus M on theflowing precipitation liquid. The liquid supplied flows from thecontainer S into the precipitating apparatus F from which the preciitation liquid again flows through the pump through the cooler K intothe container S into which powdered lime is again fed. This cycle isrepeated until the necessary tricalcium saccharate is formed, whereuponthe precipitation operation is terminated. This is the formerly knownprecipitation operation.

The liquid containing the tricalcium saccharate is then sucked away bythe pum P through the pipe 0 and is forced throug the pipe 0 into thefilter press A The solution flowing away from the filter press is ledaway through the pipe (1 into the sewer, or into a solution vaporizer ifused. The tricalcium saccharate separated in the press A is dischargedinto the masher B into which, in addition, through the pipe f dilutedcold juice (syrup or molasses) of 1 to 2% sugar content from thecollecting container D is added for mashing. The mashed saccharate isforced by the pump P from the masher B and the pipe e through the pipe einto the container R provided with a stirring apparatus. In the secondprecipitation apparatus water and dilute juice (syrup or molasses) aredeposited to form a 1 to 2% sugar solution in the collecting vessel FHereupon the pump T is putin operation to suck the initial liquid fromthe collecting vessel F 2 and the pipe 72. and to force'it through thecooler K into the container S In addition, the mashed saccharateobtained in the first process is allowed to fiow from the container Bthrough the pipe 9 into the container S The mixture flows ofi from thecontainer S into the collecting vessel F from which the pump T forcesthis liquid again into the container S This cycle is repeated untilthe'mashed saccharate in the mash is fed to the precipitation apparatus.So much saccharate is aded to the starting liquid that the quantity ofsugar in the saccharate corresponds to from one and a half to threetimes the quantity of sugar of the starting liquid. When theintroduction of this mashed saccharate is completed fresh quantities offinely powdered lime are supplied through the lime delivery apparatus Mto the circulating precipitation liquid, and this is continued until theprecipitation liquid becomes precipitated so that it contains onlyapproximately 0.5% sugar in dissolved state. Herewith the secondprecipitation operation is completed. After completion of the operationthe liquid containing the tricalcium saccharate is sucked away by thepump P through the pipe h, and is forced through the pipe k into thepress A The solution running off from this press is led away through thepipe m into the container L and is forced by thepump P through the pipen into the container L This solution serves again as a starting liquidfor a first precipitation process. The saccharate filtered ofi in thefilter press A, ar-

rives in the masher B from which the saccharate is led away through thepipe 8 into the separating station of the factory. The saccharate thusobtained has a purity efiicient of from 97 to 98. The pipe f, serves forconveying lime water to the dilute in the elements F K and S in order tofurther dilute the juice and to render it slightly alkaline.

' A second form of execution of the process I consists herein, thatinstead of a dilute su r solution lime water is used in the masher 1 forthe mashing operation. The operation. is otherwise identical with thatofthe first method.

What I claim is:

1. Process for obtaining tricalcium saccharate rich in sugar and poor inlime and of a very high co-efiicient of purit comprisin mashingsaccharate with a co dsolution 0 low sugar content in such a manner thatfrom one and a half times to three times the amount of sugar is suppliedin the formof separated tricalciumsaccharate to the su r contained insaid sugar solution, said sacc arate having been separated from amolasses solution in a Erecedm normal precipitating process, and nally ading lime to t e mixture in order to precipitate the calcium saccharatedissolved in the mixture.

2. The process according to claim 1 in i which the tricalcium saccharateis mashed with lime water and the mixture obtained is aded to said lowpercentage cold sugarsolution.

In testimony whereof I aflix m signatura CARL STEFFE Jtm'ron.

